search

eclipse / mraa

Linux Library for low speed IO Communication in C with bindings for C++, Python, Node.js & Java. Supports generic io platforms, as well as Intel Edison, Intel Joule, Raspberry Pi and many more.
http://mraa.io
MIT License
1.37k stars 613 forks source link

Info required: Use of Grove - Ultrasonic Ranger without ISR #931

Open BinduRao2018 opened 5 years ago

BinduRao2018 commented 5 years ago

Hello, I would like to test Grove - Ultrasonic Ranger using mraa on UP2 Grove Kit. As I see ISR is not yet mapped with mraa ( #888 ), could you let me know the way to test this sensor please?

Propanu commented 5 years ago

Hi @BinduRao2018, there are 2 ways I can think of. You can try to use the UPM hcsr04 driver which usually works just as well for these sensors and uses a busy wait instead of interrupts. Alternatively, if you hook the sensor directly to the UP2 board and not the GrovePi+ shield, you'll be able to use ISRs.

BinduRao2018 commented 5 years ago

Hi @Propanu , Thanks for your quick response. I am trying GrovePI+ shield on multiple platforms. So, I wouldn't be able to try an option to connect to the UP2 board directly. I went through hcsr04 driver implementation, which I would like to explore. I have one question on this: hcsr04.c expects trigger pin and echoPin - 2 pin configuration, however with the Ultrasonic ranger I will be using only one pin that acts as trigger first and then read the values. Would this work ok?

Propanu commented 5 years ago

Maybe not then, at least not out of the box. You might have to modify the hcsr04 library slightly and recompile it to use a single pin. The way the ultrasonic ranger works is the same though, as I remember at some point we were discussing merging the 2 drivers into 1 (hcsr04 and ultrasonic). @malikabhi05 has worked with these 2 libraries in the past and might be able to help.

BinduRao2018 commented 5 years ago

I tried by modifying the hcsr04 implementation to use the same pin for trigger and then echo. However, it doesn't seem to work. gpio doesn't seem to get the correct value (1 in this case) to calculate the distance. @malikabhi05 could you provide some inputs on this please?

BinduRao2018 commented 5 years ago

Any input on this please? Is there any plan to include ISR support using mraa in the near future?